Inflammation, Glucose Metabolism Disorders
Conditions
Keywords
Endotoxin, LPS, TNF-α, insulin resistance, metabolism
Brief summary
Main objective : The purpose of this study is to prove that the effects of bacterial endotoxin and cytokine TNF-α, on protein loss, fatty acid release, and glucose metabolism depend on two mechanisms: 1. Direct local effects in muscle tissue. 2. Activation of the hypothalamo-pituitary axis and a stress-hormone response Study protocols: 1. Acute metabolic effects of TNF-α(Beromun, Boehringer-Ingelheim Germany) vs placebo perfused into the femoral artery of the leg in 8 healthy subjects. 2. Acute metabolic effects of * placebo(saline) * endotoxin(US standard reference E.Coli, endotoxin) * TNF-α(Beromun, Boehringer-Ingelheim Germany) given systemically * in 8 patients with hypopituitarism(to block stress hormone release) and in 8 healthy subjects all studied thrice.
Detailed description
PURPOSE: Knowledge about the effects of bacterial endotoxin and cytokines (and inflammation in general) in humans on protein, glucose and lipid metabolism and intracellular signalling in muscle and fat is sporadic and it is uncertain whether endotoxin and cytokines act directly in fat and muscle tissue or indirectly via central nervous system (CNS) mediated stress hormone release. The investigators hypothesize that the metabolic effects of endotoxin and cytokine TNF-α, including protein loss, fatty acid release and decreased glucose uptake depend on two mechanisms: 1. Direct local effects in muscle tissue (Study protocol 1) 2. Activation of the hypothalamo-pituitary axis and generalized stress hormone response (Study protocol 2) METHODOLOGY: Study protocol 1: Acute metabolic effects of TNF-α (Beromun, Boehringer-Ingelheim, Germany) versus placebo perfused into the femoral artery of the leg in 8 healthy subjects, studied once. Femoral vein sampling allows assessment of local metabolic events in the leg. The vessels were cannulated using the Seldinger technique. Each study comprises a 3 hour basal period and a 3 hour Hyperinsulinemic-Euglycemic Clamp. Muscle biopsies were obtained simultaneously from both lateral vastus muscles. Study protocol 2: Acute metabolic effects of (i)placebo (saline), (ii)endotoxin (US standard reference E.Coli, endotoxin) and (iii)TNF-α (Beromun, Boehringer-Ingelheim, Germany) given systemically intravenously (i.v.) in 8 patients with hypopituitarism (to block stress hormone release) and in 8 healthy subjects all studied thrice. Every study comprises a 4 hour basal period and a 2 hour Hyperinsulinemic-Euglycemic Clamp. Muscle and fat biopsies were obtained. Study protocol 1 and Study protocol 2: Assays: Mass spectrometry (15N-phenylalanine, 13C-urea), 3H-glucose, 3H-palmitate quantification, hormone and metabolite analysis, cytokine assays, intracellular signaling.
Interventions
BIOLOGICALTNF-alpha
Study protocol 1: 6 ng/kg/h intraarterial Study protocol 2: 18 ng/kg/h intravenous
BIOLOGICALEndotoxin
Study protocol 2:0,075 ng/kg/h intravenous
Sponsors
University of Aarhus
Lundbeck Foundation
Aarhus University Hospital
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Masking
DOUBLE (Subject, Caregiver)
Eligibility
Sex/Gender
MALE
Age
18 Years to 70 Years
Healthy volunteers
Yes
Inclusion criteria
1. group: * Male * 19 \< BMI \< 28 * 18 ≤ Age ≤ 50 * Healthy Inclusion Criteria 2. group: * Male * 20 \< BMI \< 30 * Age \> 25 * Healthy
Exclusion criteria
* Diseases * Allergy
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Acute metabolic effects of endotoxin and cytokine TNF-α (Study 2) | 2 hours | During a basal period. Acute metabolic effects: Glucose metabolism was quantified with raw arterio-venous differences and 3H3-Glucose tracer. Lactate was quantified with raw arterio-venous differences. Lipid metabolism was quantified with \[9,10-3H\]-Palmitate tracer and amino acid metabolism with 15N-Phenylalanine tracer and 13C-Urea tracer. |
| Acute metabolic effects of cytokine TNF-α (Study 1) | 3 hours | During a basal period. Acute metabolic effects: Glucose and lactate were quantified with raw arterio-venous differences; lipid metabolism was quantified with \[9,10-3H\]-palmitate and amino acid metabolism with 15N-phenylalanine. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Intracellular insulin signaling, growth hormone signalling and inflammatory signalling pathways. | 120 min. | Musle and fat biopsies during a basal period (120 min. from the beginning of a basal period) |
Countries
Denmark
Outcome results
None listed